The pharmacokinetics of Oltipraz, a potential chemopreventive agent, will be assessed as part of an NCI-sponsored contract to perform clinical and pharmacokinetic studies of new chemopreventives. 16 normal volunteers, 4 at each of 4 dose levels, will receive a single oral dose of Oltipraz followed by collection of blood and urine for pharmacokinetic analysis. Samples will be collected over a 24 hour period in the GCRC.